package priv.pront.code.mati.province;

import java.util.Scanner;

/**
 * @Description:
 * @Author: pront
 * @Time:2023-11-17 15:08
 */
public class MC0214_捡麦子 {

    static int n, ans = 0;
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        n = scanner.nextInt();
        for (int i = 1; i <= n; i++) {
            int res = 0;
            for (int j = 0; j < i; j++) {
                res += i - j;
            }
            ans += res;
        }
        System.out.println(ans);
    }
}
